- Arm I: Patients receive DHAP induction chemotherapy comprising dexamethasone orally or IV on days 1-4, cisplatin IV continuously over 24 hours on day 1, and cytarabine IV over 3 hours every 12 hours on day 2. Beginning 3-4 weeks after DHAP, patients receive VIM induction chemotherapy comprising etoposide IV over 2 hours on days 1, 3, and 5; ifosfamide IV over 1 hour on days 1-5; and methotrexate IV on days 1 and 5. Beginning 3-4 weeks after VIM, patients with partial or complete response after DHAP and VIM receive a second course of DHAP (patients with progressive or unresponsive disease after DHAP but responsive disease after VIM receive a second course of VIM) followed by filgrastim (G-CSF) subcutaneously beginning on day 10 and continuing until a target number of cells are collected.